If teachers and administrators can't reach a deal for a new contract by Sept. 10, Chicago Teachers Union members will walk out of classrooms.

As the AP reports, the union's president said they made that decision because they were "tired of being bullied, belittled and betrayed."

The AP adds:

"Union President Karen Lewis said both sides are far apart, with teachers worried about issues that include wages, job security and a new evaluation system. If teachers do strike, it would be the district's first in 25 years and occur at the beginning of the second week of school for most students.

"'We've done everything that's been asked of us and we continue to be vilified and treated with disrespect,' she said, adding that the district's educators are 'tired of being bullied, belittled and betrayed.'"

"Lewis says the union, which issued a 10-day strike notice Wednesday, will continue negotiating until an agreement is reached."

That was the focus of Chicago Public Schools chief executive Jean-Claude Brizard.

"If our priority is our kids, then strike should never be an option," Brizard said according to NBC. "That's why we need to take advantage of each of the next 11 days and work until we reach a fair resolution for our teachers that will allow our kids to stay in school where they belong."

The Chicago Sun-Times reports that the administration made its "last, best" offer in May. That included four years of two-percent raises and scrapping all raises for "seniority and credentials."

The Sun-Times reports: "Teachers have derided the offer as "insulting," contending it does not reflect the 4 percent negotiated raise they were denied this past school year and the 10 extra days they are being required to work this school year."